A method of detecting electrical failure in a refrigeration system is provided. The method includes determining whether a present superheat of the refrigeration system is between a maximum superheat and a minimum superheat for the refrigeration system, the maximum superheat and the minimum superheat defining a normal operating range. The method also includes detecting an electrical property of an expansion valve assembly of the refrigeration system responsive to the superheat being outside the normal operating range. The method further includes determining whether the expansion valve assembly as experienced an electrical failure based on at least the electrical property. A signal indicating that the expansion valve has experienced an electrical failure is generated based on a determination that the expansion valve assembly has experienced the electrical failure.

A freezer case includes a refrigeration system and a controller. The controller is configured to store a plurality of setpoint instruction sets associated with a plurality of possible operating modes, select a current operating mode from the plurality of possible operating modes, assign a value for the superheat setpoint by executing the setpoint instruction set associated with the current operating mode, control the refrigeration system in accordance with the superheat setpoint.

A vapor compression system that includes a reheat coil that heats a supply air stream flowing across the reheat coil with a refrigerant. A fan forces an environmental air flow across a condenser to remove energy from the refrigerant. A controller adjusts a speed of the fan to control a flow of the refrigerant through the reheat coil.

A household refrigeration appliance has a thermally-insulated body with an interior container that delimits a coolable interior space, a refrigeration circuit for cooling the coolable interior space and at least one fan. During the proper operation of the household refrigeration appliance, the fan is operated in a closed loop speed-controlled manner according to an at least indirectly specified desired rotational speed of the fan. During an inspection mode, the fan is operated without closed loop speed control, the actual rotational speed of the fan is ascertained and the actual rotational speed is evaluated in order to detect an abnormal operating state of the fan.

A two-phase cooling system with flow boiling, characterized in that a closed hydraulic circuit apparatus of a heat transfer refrigerating fluid is provided, including: a pump for a refrigerating fluid which, at least in some stretches of the circuit, is two-phase liquid-vapor or multi-phase; a heat sink-evaporator configured to transfer heat by conduction from a component to be cooled to the refrigerating fluid; a condenser, capable of condensing the vapor which develops on the evaporator while simultaneously dissipating the heat given by the refrigerating fluid both by conduction, convection and radiation and by condensation into the environment; a tank which also acts as an expansion vessel, or a tank and an expansion vessel which are distinct and connected to each other; and a plurality of sensors, including flow rate, pressure and temperature sensors and an electronic control system of the pump.

A compressed air drying system is provided for removing moisture from compressed air. The dryer operates in two modes in response to the demand for compressed air. In a first mode of operation, a refrigeration compressor runs continuously and the speed of a condenser fan is varied to maintain a constant cooling temperature. In a second mode of operation, the refrigeration compressor runs intermittently between on and off periods. As result, the cooling temperature fluctuates during the second mode of operation.

An air-conditioning apparatus includes a first indoor unit and an outdoor unit in a single refrigeration cycle and connected via a first refrigerant pipe. The first indoor unit is provided with a first refrigerant leakage sensor configured to detect leakage of refrigerant and a concentration of leaked refrigerant, and the outdoor unit includes a compressor, a first flow control valve configured to adjust a flow rate of the refrigerant flowing through the first refrigerant pipe, and a control unit configured to stop the compressor and fully close the first flow control valve when leakage of the refrigerant flowing through the first refrigerant pipe is detected by the first refrigerant leakage sensor, and configured to change an opening speed of the first flow control valve to a speed less than an opening speed of the first flow control valve adopted before the leakage of the refrigerant is detected.

An air conditioning system is provided. The system has a high-pressure pipe, a low-pressure pipe, an indoor heat exchanger, an outdoor heat exchanger, a leak-free thermal expansion valve and a variable capacity compressor. The variable capacity compressor has a shell, a first cylinder and a second cylinder. The shell has a suction port and an exhaust port. The first cylinder has a first suction hole connected to the suction port and a first exhaust hole connected to the exhaust port. The second cylinder has a second suction hole connected to the suction port, a second exhaust hole connected to the exhaust port, and a pressure relief hole connected to the high-pressure pipe and the low-pressure pipe in an on-off manner. Before the variable capacity compressor is started, the high-pressure pipe and the low-pressure pipe are connected and also disconnected after the first preset duration.

A refrigeration system includes a heat exchanger configured to place a cooling fluid in a heat exchange relationship with a working fluid, a free-cooling circuit having a pump configured to circulate the working fluid through the heat exchanger and a condenser, a flow control valve configured to control a flow rate of the working fluid to the condenser, a condenser bypass valve configured to control a flow rate of the working fluid that bypasses the condenser, and a controller configured to adjust a position of the flow control valve, a position of the condenser bypass valve, a speed of a fan of the condenser, a speed of the pump, and a temperature of a heater based on an ambient temperature, a temperature of the working fluid leaving the condenser, the position of the flow control valve, the position of the condenser bypass valve, or a combination thereof.

A CO.sub.2 based refrigeration system and a method of operating the CO.sub.2 based refrigeration system. The system includes a condenser configured to transfer heat from a CO.sub.2 refrigerant of the refrigeration system to an air stream. The system also includes an indirect evaporative cooler arranged to cool an ambient air stream without changing its moisture content and to supply the cooled ambient air to the condenser to facilitate the transfer of heat from the CO.sub.2 refrigerant.